With development of liquid crystal display technology, liquid crystal display panels used for wearable devices are gradually emerging. The liquid crystal display panel of the wearable device has a small size, and is manufactured by a method different from that for manufacturing a conventional liquid crystal display panel. The conventional liquid crystal display panel has a pixel structure in which a pixel electrode is charged by a data line, thus hundreds of gray scales may be realized according to different voltages of the data line. By contrast, the liquid crystal display panel of the wearable device has a pixel structure including a digital circuit, only two gray scales, i.e., a first gray scale and a second gray scale, can be realized according to high and low levels of a digital signal.
The liquid crystal display panel of the wearable device is generally manufactured by a low temperature polycrystalline silicon thin film transistor process, a latch is formed by a logic gate circuit, and a voltage of the pixel electrode is maintained. A common method for maintaining the voltage of the pixel electrode is to employ a buffer, i.e., two inverters with end to end connection, in such way, when an input of data signal is turned off, an output signal is circulated in the buffer, thus is maintained.